Decomposed Electricity and Natural Gas Optimal Power Flow

Different energy infrastructures, such as electricity, natural gas and local district heating systems utilized for the energy supply are most often planned and operated independently of each other. This paper addresses the optimization of combined electricity and natural gas networks. The couplings between the two energy infrastructures are taken into account with the novel concept of energy hubs which enables the analysis of a combined optimal power flow (OPF). Energy systems are built up by interconnected energy hubs and thus form a distributed power generation structure. Each hub is controlled by its respective control authority yielding a distributed control structure. A method is presented, decomposing a central OPF problem into subproblems solved in an iterative way, independently but coordinated. This method has successfully been applied to electric power systems. In this paper, the decomposition method is extended and applied to the combined electricity and natural gas OPF. Simulation results are presented, applying the procedure to an illustrative system of three interconnected energy hubs.